Microform images are useful in archiving a variety of documents or records by photographically reducing and recording the document in a film format. Examples of typical microform image formats include microfilm/microfiche, aperture cards, jacketed microfiche, 16 mm or 35 mm film roll film, cartridge film, both positive and negative, and other micro opaques. For example, a microfiche article is a known form of graphic data presentation wherein a number of pages or images are photographically reproduced on a single “card” of microfiche film (such as a card of 3×5 inches to 4×6 inches, for example), or a roll of film. A large number of pages (up to a thousand or so) may be photographically formed in an orthogonal array on a single microfiche card of photographic film. The microfiche film may then be placed in an optical reader and moved over an optical projection path of a film reader until a selected page is in the optical projection path. The reader generates an image of the selected page, which is then presented on an imager screen for viewing. Although other electronic, magnetic or optical imaging and storage techniques and media are available, there exists an extensive legacy of film type records storing the likes of newspapers and other print media, business records, government records, health records, genealogical records, and the like.
Most rolls of microfilm can contain thousands of document images. These documents are generally ordered numerically or chronologically, although any arrangement is possible. Most often when roll film is used, a user may desire to locate or view only one, or just a few, of the documents on the roll. Finding the desired document(s) can represent a significant challenge of using microfilm. Once the roll of film is loaded onto a microform imaging apparatus, a user could search for the desired document by advancing the film slowly while viewing pertinent information, such as numbers or dates on every document. However, to read this information, the film must be advanced very slowly. Using this method to find the one document among the possible thousands would take a very long time. To speed up the search process, the user can employ a trial and error approach, using fast forward and fast reverse roll film motor controls to more quickly move the film to a general location within the roll of film, and then by using the slow roll film motor controls to ultimately find the desired document. Even the most experienced user wastes a great deal of time finding a desired document in this way.
To speed up this search process, over the years and still today, some rolls of microfilm contain, not only the possible thousands of document images, but also an Image Mark (IM) by each image (see FIGS. 23-27 for examples of IMs). Furthermore, a separate index can be created for each of these rolls identifying the precise location of each document based on the IMs. If a microform imaging apparatus is designed to read these IMs, a user, armed with this index, can direct the microform imaging apparatus to automatically move the roll of film to the desired image, typically in just a few seconds.
There are several standards used for these IMs, with the “IM Standard ISO 11926” and “IMS Standard Cannon & Kodak” describing the most commonly used IM standards (see FIG. 27 for examples). These IMs are a form of bar code, however, this is not a bar code of the type that is typically seen today (many bars of various widths identifying each item in great detail) but rather a single bar for each document image. The standards define that this single bar could be any one of three widths. Each width indicates something about the document. For example, the widest is typically the start of a batch, the middle width typically indicates the start of a file, whereas the narrowest width indicates a page within a batch or file. Rolls of IM'ed film may contain only one width of IMs, other rolls may contain two widths of IMs, and some may contain IMs of all three widths.
Known microform imaging apparatus have used two basic methods to read these IMs. One method is to put dedicated optical sensors in the film path, whereby the IMs are read directly off the film using only the designated sensor. The other method is to put dedicated optical sensors at the viewing screen to read the IMs projected onto that screen. Here still, the dedicated sensor only reads the IM that is projected on the screen. If the film is not held in the correct position in the film path, these sensors can miss the IM altogether, thereby providing inaccurate results.
What is needed in the art is improved systems and methods that can sense an IM on the microform containing the image of a document.